Integrated circuit, circuit system, and method of manufacturing

ABSTRACT

An integrated circuit, a circuit system and method of manufacturing such is disclosed. One embodiment provides a circuit chip including a first contact field on a chip surface; and an insulating layer on the chip surface. The insulating layer includes a flexible material. A contact pillar is coupled to the first contact field and extends from the chip surface through the insulating layer. The contact pillar includes a conductive material.

BACKGROUND

Integrated circuit systems include integrated circuits having circuitchips arranged on a semiconductor substrate coupled to a circuit board.Circuit systems, integrated circuits, and circuit boards may besubjected to temperature variations. A difference in the thermalexpansion coefficients of the constituent materials and components mayresult in mechanical stress or even a rupture of electrical connectionsand/or components of the circuit system.

For these and other reasons, there is a need for the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments andtogether with the description serve to explain principles ofembodiments. Other embodiments and many of the intended advantages ofembodiments will be readily appreciated as they become better understoodby reference to the following detailed description. The elements of thedrawings are not necessarily to scale relative to each other. Likereference numerals designate corresponding similar parts.

FIGS. 1A through 1C illustrate schematic cross-sectional views of acircuit system according to one embodiment.

FIGS. 2A through 2J illustrate integrated circuits according to one ormore embodiments.

FIGS. 3A through 3H illustrate an integrated circuit and a circuitsystem in various stages during manufacturing according to oneembodiment.

FIGS. 4A through 4D illustrate an integrated circuit in various stagesduring manufacturing according to one embodiment.

DETAILED DESCRIPTION

In the following Detailed Description, reference is made to theaccompanying drawings, which form a part hereof, and in which is shownby way of illustration specific embodiments in which the invention maybe practiced. In this regard, directional terminology, such as “top,”“bottom,” “front,” “back,” “leading,” “trailing,” etc., is usedembodiments can be positioned in a number of different orientations, thedirectional terminology is used for purposes of illustration and is inno way limiting. It is to be understood that other embodiments may beutilized and structural or logical changes may be made without departingfrom the scope of the present invention. The following detaileddescription, therefore, is not to be taken in a limiting sense, and thescope of the present invention is defined by the appended claims.

It is to be understood that the features of the various exemplaryembodiments described herein may be combined with each other, unlessspecifically noted otherwise.

FIG. 1A illustrates an integrated circuit system according to oneembodiment. The circuit system includes an integrated circuit 100 and acircuit board 200. The integrated circuit 100 includes contact pads 1001on a circuit surface which faces the circuit board 200. The circuitboard 200 includes contact pads 2001 being arranged on a board surface,which faces the integrated circuit 100. The integrated circuit 100 maybe connected to the circuit board 200 by using solder connections 300connecting contact pads 2001 to respective contact pads 1001 of theintegrated circuit 100.

The integrated circuit 100 includes a circuit chip 1006, which, in turn,may include a semiconductor substrate, an integrated circuit, a memorychip, a processor chip, an integrated circuit chip, and/or a stackthereof. On a chip surface of the circuit chip 1006 there are arrangedsignal lines 1005. The signal lines 1005 may include or form aredistribution layer (RDL) such to reroute signals from one position onthe chip surface to another. On the chip surface of the circuit chip1006 there is arranged an insulating layer 1003 which includes aflexible material 1004. The integrated circuit 100 further includescontact pillars 1008 which are arranged, at least in part, in theinsulating layer 1003 and include a conductive material 1002. A packagematerial 1007 may further encapsulate the circuit chip 1006 and mayreach down to the insulating layer 1003.

The circuit board 200 includes a board material 2002, which may possessa coefficient of thermal expansion (CTE), such as a second coefficientof thermal expansion CTE2. The circuit chip 1006 of the integratedcircuit 100 may include a chip material 1009, which possesses acoefficient of thermal expansion, such as a first coefficient of thermalexpansion CTE₁. In general, the two CTEs, CTE₁ and CTE₂, may differ,although they may be approximately equal and/or engineered such to beclosely matched. However, even a small difference in the two CTEs, suchas 10% or 1%, may result in different thermal expansion properties. Forexample, the chip material 1009 may include a semiconductor, such assilicon, whereas the circuit board 200 may include a board material2002, such as an epoxy resin and/or glass. Respective CTEs for a chipmay be in a range of 1 ppm to 5 ppm, and for the board in a range of 10ppm to 20 ppm. As a further example, circuit systems such as wafer levelpackages (WLP) may require a maximum distance from an outer solderconnection to a circuit chip center, since, by exceeding that maximumdistance, rupture of connections may occur. Such a maximum distance maybe denoted by a distance to neutral point (DNP).

Since circuit systems, integrated circuits, and circuit boards as suchmay be subject to temperature variations, a difference in the thermalexpansion coefficients of the constituent materials and components, may,in turn, result in mechanical stress or even a rupture of electricalconnections and/or components of the circuit system. Examples ofmaterials and components which may be prone to such a mechanical stressinclude the circuit chip 1006, the contact pads 1001, the contact pads2001, the circuit board 200, and/or the solder connections 300.

FIG. 1B illustrates a schematic cross-sectional view of the circuitsystem, including the integrated circuit 100 and the circuit board 200,according to one embodiment. As illustrated in FIG. 1B a systemtemperature has been changed in respect to the situation as has beenillustrated and described in conjunction with FIG. 1A. Since the chipmaterial 1009 and the board material 2002 may possess differentcoefficients of thermal expansion, an effective expansion of the boardmaterial 2002 and chip material 1009, and, as a result, an effectiveexpansion of the circuit board 200 and the integrated circuit 100 maydiffer. As illustrated here, the circuit board 200 has expanded morethan the integrated circuit 1 00. For the sake of clarity, the effect ofexpansion may have been illustrated in an exaggerated form, hence, nocomparison to real values of thermal expansions should be made accordingto the drawings and/or the scale thereof.

According to one embodiment, the insulating layer 1003 includes aflexible material 1004. This flexible material 1004 may be structured byusing photo-lithography or, in general, radiation lithography. Theflexible material 1004 may furthermore be an insulating material, andmay include any material of the group of a photoresist material, apermanent photoresist material, a chemically amplified photo resist, aresin, an epoxy resin, epoxy bis-phenol-A novolakoliomer, a sulphoniumcrivello salt, γ-butyro-lacton, cyclo-pentanone,polymethylmethaacrylate, TMMF, TMMR, and NANO™ SU-8, and combinationsthereof Accordingly, the contact pillars 1008 may include a conductivematerial 1002. The conductive material 1002 may furthermore be aconductive material, such as to form a conducting contact pillar 1008.The conductive material 1002 may be or include a low melting pointmaterial, a solder material, a solder alloy, a bond wire material, tin,copper, silver, lead, bismuth, indium, gold, and/or aluminium. Themelting point of the conductive material 1002 may not exceed thetemperature stability of the flexible material 1004.

Since in FIG. 1B there is illustrated a situation, wherein the circuitboard 200 expands more than the integrated circuit 100, and/or thecircuit chip 1006, the flexible material 1004 of the insulating layer1003 and the conductive material 1002 of the contact pillars 1008 maycompensate for such a different expansion. In such a way, a ruptureand/or decrease of conductivity of a connection between the integratedcircuit 100 and the circuit board 200 may be prevented. In this way, thecircuit system, including the integrated circuit 100 and the circuitboard 200 may be subjected to an increased number of thermal cycles, anincreased number of operation cycles, an increased number of start-upsequences, to an increased difference between a minimum and a maximumstorage temperature, and/or to an increased difference between a minimumand a maximum operation temperature. In such a way, the circuit systemmay also have a larger maximum distance of the outer solder connectionto a circuit chip center (DNP). Furthermore, the integrated circuit 100and the circuit board 200 may be subjected to an increased processtemperature during soldering. The mechanical properties of the flexiblematerial 1004 and the conductive material 1002 may provide such acompensation.

As illustrated in FIG. 1C, the situation of different expansions of thecircuit chip 1006 and the circuit board 200 may be opposite to thesituation as has been described in conjunction with FIG. 1B. In such acase, the circuit chip 1006 and/or the integrated circuit 100 may expandmore than the circuit board 200, or the circuit board 200 may expandless than the integrated circuit 100 and/or the circuit chip 1006. Themechanical properties of the flexible material 1004 and the conductivematerial 1002 may provide also in such a situation a reliable contactingand/or a suppression of any contact ruptures or an undesired attenuationof the conductivity of connections within the integrated circuit 100,the circuit board 200, or the circuit system. As illustrated here, thecontact pillar 1008 and the insulating layer 1003 are bended inward,such to compensate for the larger expansion of the integrated circuit100 or the lesser expansion of the circuit board 200.

FIG. 2A illustrates an integrated circuit 101 according to oneembodiment. The integrated circuit 101 includes a circuit chip 1011,such as the circuit chip 1006, which has been described in conjunctionwith FIGS. 1A through 1C. On a chip surface of the circuit chip 1011there are arranged the signal lines 1005. The signal lines 1005 providesignal routing from one position of the chip surface of the circuit chip1011 to a respective position of a contact pillar 1008 within thatplane. On the chip surface of the circuit chip 1011 there is arranged aninsulating layer 1010, including the flexible material 1004. A thicknessof the insulating layer 1010 may be in a range of 20 μm to 100 μm. Thecontact pillars 1008, including the conductive material 1002, couple therespective signal line 1005 to a contact pad 1001, which is arranged ona circuit surface of the integrated circuit 101. A diameter of thecontact pillars 1008 may be in a range of 10 μm to 50 μm.

On the contact pads 1001 there may be arranged solder balls 1012. Suchsolder balls 1012 may provide a reliable connection of the integratedcircuit 101 to an external circuitry, such as a circuit board, a printedcircuit board (PCB), or a circuit system. In general, such solder ballsmay also be omitted, since integrated devices may also be connected to acircuit system by using providing a solder paste onto the integratedcircuit and/or a respective circuit board prior to a soldering process.A cross section of the contact pillars 1008 may include a diameter in arange of 15 μm to 50 μm, a diameter of a contact pad 1001 may be in arange of 150 μm to 250 μm, and a diameter of a solder ball 1012 may bein a range of 150 μm to 400 μm.

FIG. 2B illustrates an integrated circuit 102 according to oneembodiment. Accordingly, the integrated circuit 102 includes groups 1021of contact pillars, which include the conductive material 1002. Thegroups 1021 of contact pillars may connect signal lines 1022 to contactpads 1023. The signal lines 1022 are arranged on a chip surface of thecircuit chip 1011. In turn, the contact pads 1023 are arranged on acircuit surface of the integrated circuit 102. The groups 1021 of thecontact pillars may provide an increased conductivity, a conductivityfor an increased current, a matched impedance, an increased conductivityfor high frequency signals, and/or a waveguide. The circuit chip 1011may require such an increased conductivity and/or a matched impedanceconnection. The integrated circuit 102 may furthermore include more thanone group 1021 of contact pillars, different groups of contact pillars,and/or groups 1021 of contact pillars and single contact pillars. Solderballs 1012 may be arranged on the contact pads 1023.

The groups 1021 of the contact pillars may include outer contact pillars1024 and a central contact pillar 1025, the outer contact pillars 1024being arranged along an outer circle in a coaxial configuration aroundthe central contact pillar 1025. In this way, a coaxial configurationmay be achieved, and the outer contact pillars 1024 may be coupled to acommon reference potential, such as a ground potential, whereas thecentral contact pillar 1025 may carry a high-frequency signal or anelectromagnetic wave. The radius of the outer contact pillars 1024, thedistance of an outer contact pillar 1024 to the central contact pillar1025, and/or the dielectric properties of the flexible material 1004 maydetermine a characteristic frequency for a transmission of highfrequency signals. High frequency (HF) signals may be any signals withan effective frequency above 100 MHz, above 500 MHz, or above 1 GHz.

FIG. 2C illustrates an integrated circuit 103 according to oneembodiment. The insulating layer 1010 is arranged on the circuit chip1011 and connected by using signal lines 1005 to contact pillars 1008.The insulating layer 1010 includes the flexible material 1004, whereasthe contact pillars 1008 include the conductive material 1002.

According to one embodiment, there is arranged a further signal line1030 on the insulating layer 1010. The further signal line 1030 may bepart or form a second redistribution layer (RDL). In conjunction withthe signal lines 1005, the further signal lines 1030 may provide furtherredistribution of the signals from one position to another. In this way,signal path crossings may be achieved without short circuiting therespective signal lines. The signal lines 1030 may include contact pads1032, on which there may be arranged solder balls 1012. The signal lines1030 may further include a further contact pad 1033, which is coupled tothe respective contact pillar 1008. The further contact pad 1033 iscoupled to the contact pad 1032 via signal lines 1034. A solder maskand/or a solder stop material 1031 may be arranged on the insulatinglayer 1010. The solder mask 1031 may prevent an undesired shortcircuiting of further signal lines 1030, upon liquefaction of the solderballs 1012.

FIG. 2D illustrates an integrated circuit according to anotherembodiment. The integrated circuit 104 includes the circuit chip 1011 onwhich there are arranged the signal lines 1005. According to thisembodiment, the integrated circuit 104 includes a first insulating layer1041 and a second insulating layer 1042. The first insulating layer 1041and the second insulating layer 1042 include the flexible material 1004.In the two insulating layers 1041, 1042 there are arranged contactpillars 1008. On a circuit surface of the second insulating layer 1042there are arranged the contact pads 1001, on which, in turn, there maybe arranged solder balls 1012. On the second insulating layer 1042 theremay be further arranged the solder mask 1031.

According to this embodiment, the circuit chip 1011 is connected to thecontact pads 1001 by using the signal lines 1005, contact pillars 1008within the first insulating layer 1041, further signal lines 1043, andthe contact pillars 1008 within the second insulating layer 1042. Theprovision of a further signal line 1043, and/or the provision of thesecond insulating layer 1042 may allow further redistribution of signalsfrom one position of a circuit chip plane to another. In addition tothis, signal crossings may be realized without short circuiting.

FIG. 2E illustrates an integrated circuit according to one embodiment.The integrated circuit 105 includes the circuit chip 1011, theinsulating layer 1010, the contact pads 1001 on a circuit surface on theinsulating layer 1010, contact pillars 1008, and the signal lines 1005.The contact pads 1001 are coupled to the circuit chip 1011 by using thecontact pillars 1008 and the signal lines 1005. On the contact pads 1001there may be arranged the solder balls 1012.

According to this embodiment, the integrated circuit 105 includes apackage 1050, which, in turn, includes a package material 1051. Thepackage material 1051 may include a resin, a ceramic material, apolymer, and/or a combination thereof. The package material 1051 of thepackage 1050, at least in part, surrounds the circuit chip 1011 and theinsulating layer 1010. The package material 105 1 may possess mechanicalproperties, such as to allow for an expansion or contraction of theinsulating layer 1010 and/or the circuit chip 1011. Furthermore, in thecase that the package material 1051 possesses a reduced flexibility inrespect to the flexible material 1004, the mechanical properties of theflexible material 1004 may be such that to compensate for theconfinement by the package 1050 according to this embodiment. Theintegrated circuit package as illustrated in FIG. 2E may be alsoreferred to as a fan-in universal package.

FIG. 2F illustrates an integrated circuit according to one embodiment.The integrated circuit 106 includes the circuit chip 1011 which iscoupled to signal lines 1061. According to this embodiment, theinsulating layer 1062, including the flexible material 1004, extendsfrom a footprint of the circuit chip 1011. The signal lines 1061 mayfurther extend from such a footprint and provide connections to contactpads 1001, which may, in this way, be arranged on a larger area than thefootprint of the circuit chip 1011 and/or outside such a chip footprint.Although modern circuit chips may provide a plurality of contacts on alimited circuit chip surface, such as in a high density configuration,this contact density may not be matched or cannot be matched by solderconnections and/or contact pads toward an external circuitry, such as acircuit board or a printed circuit board (PCB).

According to this embodiment, the enlarged insulating layer 1062—inrespect to the footprint of the circuit chip 1011—may provide both aredistribution of signals to a larger area and/or a flexibility, in thecase that the material of the circuit chip 1011 and a material of anexternal circuitry possess different coefficients of thermal expansion.The integrated circuit 106 further includes a package 1060, includingthe package material 1051. The package 1060 surrounds, at least in part,the circuit chip 1011 and may form an interface to the insulating layer1062. In this way, the insulating layer 1062 may be arranged as acontinuous and/or smooth layer on the circuit chip 1011 and the package1060. The flexible material 1004 of the insulating layer 1062 may inthis way expand or contract in order to provide a compensation ofdifferent coefficients of thermal expansion (CTE). The integratedcircuit package as illustrated in FIG. 2F may be also referred to as afan-out universal package.

FIG. 2G illustrates an integrated circuit according to one embodiment.The integrated circuit 107 includes the circuit chip 1011. On a chipsurface of the circuit chip 1011 there are arranged signal lines 1070and an insulating layer 1071. On the insulating layer 1071 there arearranged contact fields 1073 and contact fields 1074. On the contactfields there may be arranged solder balls 1012.

According to this embodiment, the insulating layer 1071 includestrenches 1072. The trenches 1072 may reach to the chip surface of thecircuit chip 1011. However, the trenches 1072 may be such that theirdepth is less than the thickness of the insulating layer 1071, in thisway, forming an insulating layer 1071 which continuously covers thecircuit chip 1011. Accordingly, the insulating layer 1071 providesislands of the flexible material 1004. Within such an island, one ormore contact pillars 1008 may be arranged, such as to couple the signallines 1070 to respective contact pads. One island may include just onecontact pillar or a group thereof.

The trenches 1072 may be provided such to provide an enhancedflexibility of the insulating layer 1072, rendering the manufacturingmore independent from material properties: In this way, the flexibilityof the flexible material 1004 may be reduced and/or allows theapplication of a less flexible or unflexible material for the flexiblematerial 1004. In the case that one island of the insulating layer 1071includes only one contact pillar, a contact pad 1073 may be coupled tothe respective contact pillar, and such an island may, over all, bearranged as a coaxial column, including the flexible material 1004 and,in the center, the conductive material 1002.

FIG. 2H illustrates an integrated circuit according to one embodiment.The integrated circuit 108 includes the circuit chip 1011 and aninsulating layer 1080. The insulating layer 1080 is arranged on a chipsurface of the circuit chip 1011. Signal lines 1082 provide a routing ofsignals from one position of the chip surface to the position of arespective contact pillar 1008 and/or contact pillar 1081. The contactpillars 1008, 1081 include a conductive material 1002, whereas theinsulating layer 1080 includes the flexible material 1004. On a circuitsurface there are arranged contact pads 1001, on which, in turn, theremay be arranged solder balls 1012.

According to this embodiment, the contact pillar 1081 provides anenhanced cross section in respect to the contact pillar 1008. In thisway, a contact pillar 1081 may provide an increased conductance, and/ormay conduct a greater current than the contact pillars with a smallercross section, such as the contact pillars 1008. In this way, contactswith increased conductivity, for example, for using power supply orother power applications, may be provided to the circuit chip 1011,whereas contacts that require a normal conductivity, such as signalcontacts, may be provided with a smallest possible cross section in theinsulating layer 1080. In this way, a high density configuration ofcontact pillars 1008 may be provided, while, at the same time, allowingfor a provision of an increased and/or enhanced conductivity forselected contacts.

FIG. 21 illustrates an integrated circuit according to one embodiment.The integrated circuit 109 includes the circuit chip 1011, signal lines1094, contact pillars 1008, contact pads 1001, and an insulating layer1093. The signal lines 1094 couple respective signals from the circuitchip 1011 by using the contact pillars 1008 to the respective contactpads 1001.

According to this embodiment, the integrated circuit 109 includes acoaxial configuration of a center contact pillar 1092 and a surroundinghollow contact column 1091. The contact column 1091 and the centercontact pillar 1092 are embedded in the flexible material 1004. Arespective signal line 1094 may conduct a high frequency signal or anelectromagnetic wave from the circuit chip 1011 to a respective contactpad configuration on the circuit surface on the insulating layer 1093.Such a contact pad configuration may include a center pad 1095 and aring pad 1096. The outer diameter of the center contact pillar 1092, theinner diameter of the hollow contact column 1091, and/or the dielectricproperties of the flexible material 1004 may be engineered, selected,and/or be such that a characteristic frequency for the transmission of ahigh frequency signal is achieved.

FIG. 2J illustrates an integrated circuit according to one embodiment.An integrated circuit 110 includes the circuit chip 1011, signal lines1005, contact pillars 1008, contact pads 1001, solder balls 1012, and aninsulating layer 1 102. The insulating layer 1102 includes the flexiblematerial 1004, whereas the contact pillars 1008 include the conductivematerial 1002.

According to this embodiment, the conductive material 1002 isfurthermore arranged on an edge or on a side face of the integratedcircuit 110. This may form a corner column 1104 including the conductivematerial 1002. The corner column 1104 may extend through the insulatinglayer 1102 and/or the circuit chip 1101. The integrated circuit 110 mayfurther include a side plate 1103 including the conductive material 1002on a side face of the integrated circuit 1 10. The corner column 1104and/or the side plate 1103 may provide a mechanical protection of theintegrated circuit 110 during manufacturing, connecting, assembly,and/or operation.

FIG. 3A through 3H illustrate an integrated circuit and a circuit systemincluding the integrated circuit in various stages during manufacturingaccording to one embodiment. As illustrated in FIG. 3A a circuit chip3000 is provided. The circuit chip 3000 may include a semiconductorsubstrate or a stack thereof. The semiconductor substrate may includefunctional entities, such as transistors, resistors, conductors,capacitors, diodes, inductors, insulators, dielectrics, capacitors,light-emitting diodes, semiconductor lasers, light sensors, and relatedentities such to form an integrated circuit. Examples of the circuitchip 3000 include a memory chip, a processor chip, an integrated circuitchip, a signal processor chip, and the like.

The circuit chip 3000 includes contact fields 3001 on a chip surface ofthe circuit chip 3000. The contact fields 3001 are coupled to thefunctional entities, such as to allow for an electrical connection tothe integrated circuit, being comprised by the circuit chip 3000. On thechip surface of the circuit chip 3000 there is arranged a passivatinglayer 3003, providing insulation and/or mechanical, physical, orchemical insulation of the circuit chip 3000. The passivating layer 3003includes openings 3002 in an area of the contact fields 3001, in orderto allow for a connection to the contact fields 3001. The contact fields3001 may include FE-pads.

As illustrated in FIG. 3B, signal lines 3004 are provided on the chipsurface of the circuit chip 3000, establishing a contact to the contactfields 3001. The signal lines 3004 may be part or form a redistributionlayer, such as to allow for a rerouting of a signal from a position ofthe contact field 3001 to another position in the chip plane. The signallines 3004 may be provided by using depositing a conductive layer, suchas a metal layer, and a subsequent structuring of the conductive layer.Structuring, in turn, may include photolithography, UV-lithography,electron beam lithography, developing, anisotropic etching, and/orselective wet etching.

As illustrated in FIG. 3C, an insulating layer 3005 is provided on thechip surface, covering the signal lines 3004. The insulating layer 3005includes the flexible material 1004, as this has been described inconjunction with one embodiment.

As illustrated in FIG. 3D, openings 3006 are provided in the insulatinglayer 3005. In the case that the insulating layer 3005 includes aphotosensitive material, the openings may be created by aphotolithographic process, which, in turn, may include a selectedexposure to radiation, such as light, UV-light, or an electron beam, anda subsequent developing of the exposed layer. Providing the openings3006 may include a provision of an etching mask on a surface of theinsulating layer 3005 and an etching process, such as an anisotropicetching, reactive ion etching, and/or ion etching. The openings 3006 areprovided on respective positions, in order to allow an access of therespective signal lines 3004.

As illustrated in FIG. 3E, the openings 3006 of the insulating layer3005 are filled with the conductive material 1002, such as to formcontact pillars 3008. In this way, a contact may be established to thesignal lines 3004, being still accessible by a respective cross sectionof the contact pillar 3008 on a surface of the insulating layer 3005.

As illustrated in FIG. 3F, contact pads 3009 are provided on a surfaceof the insulating layer 3005, such as to establish a contact to thecontact pillars 3008, and, in turn, to the signal lines 3004. In thisway, the function entities and/or the integrated circuit being comprisedby the circuit chip 3000 may be connected by using connecting to thecontact pads 3009. The provision of the contact pads 3009 may beeffected by using a sputtering, a plating, and/or a photolithographictechnique. An initially continuous layer may be structured such toprovide individual contact pads and/or signal lines.

As illustrated in FIG. 3G solder balls 3010 are provided on the contactpads 3009. In this state during manufacturing, or in the state as hasbeen described in conjunction with FIG. 3F, a ready integrated circuit3200 may be formed, which may be shipped, handled and/or processedseparately. The solder balls 3010 may be provided by using a ball-droptechnique, or may be replaced or effected by a provision of a solderingpaste.

As illustrated in FIG. 3H, the integrated circuit 3200 is connected to acircuit board 3013 in order to form a circuit system, such as a circuitsystem which has been described in conjunction with FIGS. 1A through 1C.The circuit board 3013, may be or include a printed circuit board and/orother integrated circuits, such as to form a circuit system, such as acomputer system, a memory module, a system in package, a multi-chipmodule, a mainboard, a graphics board, and/or an application board. Theintegrated circuit 3100 is connected to the circuit board 3013 by usingsolder connections 3011, which connect the respective contact pads 3009to respective contact pads 3012 which are arranged on the circuit board3030. Suitable soldering processes include flux-dipping, reflowsoldering, infrared soldering, and related techniques.

FIGS. 4A through 4D illustrate the integrated circuit 3100 in variousstages during manufacturing according to one embodiment. According tothis embodiment, the openings 3006 in the insulating layer 3005 arefilled with the conductive material 1002 by using a pressure-inducedfilling process. As illustrated in FIG. 4A the integrated circuit 3100in this stage during manufacturing is provided within a processatmosphere 4001. The process atmosphere 4001 may provide a firstpressure, may be a vacuum or a low pressure atmosphere with a firstpressure which is less than a second pressure. The integrated circuit3100 is provided in this process atmosphere 4001 in a vicinity to a bath4002 of the conductive material 1002 in a viscous or a liquid state.

As illustrated in FIG. 4B the liquid conductive material 1002 isprovided around an aperture of the openings 3006 of the insulating layer3005, by using, for example, dipping the integrated circuit 3100 intothe bath 4002. During this stage the first process atmosphere 4001 and arespective pressure still acts in the openings 3006 of the insulatinglayer 3005.

As illustrated in FIG. 4C, a second process atmosphere 4003 is providedaround the bath 4002 of the conductive material 1002. A pressure of thesecond process atmosphere 4003 may be an atmospheric pressure, a highpressure, or a second pressure which is larger than the first pressure.In this way, the liquid flexible material 1002 is pressed into theopenings 3006 of the insulating layer 3005. In this way an intermediateintegrated circuit 3199 is formed, including filled openings within theinsulating layer 3005.

As illustrated in FIG. 4D, the integrated circuit 3199 is extracted fromthe material bath 4002, wherein the openings 4006 still remained filledwith the liquid material 1002. By using a solidification of the liquidmaterial 1002 in the openings 4006 of the insulating layer 3005, contactpillars 3008 are formed, which provide an integrated circuit 3200.Solidification may be effected by using cooling the integrated circuit3199 below a melting temperature of the conductive material 1002. Forexample, the material bath 4002 may be a bath of a solder material, theconductive material 1002 being a solder material, and including, forexample, tin, lead, copper, silver, bismuth, indium, urea, zincchloride, colophony, and or a flux material. In such a case, theintegrated circuit 3199 may be cooled below the melting temperature suchas to form solid and reliable contact pillars 3008. In the case ofcommon solder materials, such a melting temperature may be in a range of150° C. to 250° C. In this way, at normal, ambient temperatures and/oreven elevated operation temperatures, the conductive material 1002 mayremain solid and may provide a reliable and stable contact pillar 3008.

According to one embodiment, a conductive spacer, such as the contactpillars, may be formed by such a method, while providing processsimplicity, reliability, low cost, and an enhanced aspect ratio above2:1. The aspect ratio is the ratio of a length of a conductive spacerdivided by a width of such a spacer.

According to another embodiment, a high aspect ratio provides a reducedcross section of a contact pillar, which may, in turn, reduce athermo-mechanical coupling between the contact pad and the respectivesignal line. This may be an advantage, if circuit chips includestress-sensitive materials, such as high-k dielectric materials.

According to yet another embodiments of the present invention, anunderfilling of an wafer level package (WLP) may be rendered obsolete, arobustness of a WLP or circuit system may be increased, a robustness ofa WLP or circuit system against dropping may be increased, a robustnessof a WLP or circuit system against mechanical shocks may be increasedand/or standard solder balls may be applied.

According to yet another embodiments, the flexible material may be orinclude an insulating material. The integrated circuit may furthermoreinclude a first signal line between the circuit chip and the insulatinglayer, the first signal line coupling the first contact field to thecontact pillar. Additionally, the integrated circuit may include acontact pad on the insulating layer, the contact pad being coupled tothe contact pillar. Also, the integrated circuit may include a secondsignal line on the insulating layer, the second signal line coupling thecontact pad to the contact pillar. Furthermore, the insulating layer mayinclude a trench.

According to yet further embodiments, the printed circuit board mayinclude a board material with a first coefficient of thermal expansionand the circuit chip including a chip material with a second coefficientof thermal expansion. Furthermore, the first coefficient of thermalexpansion and the second coefficient of thermal expansion may differ atleast by 10 per cent.

According to a further embodiment, a liquid state of the conductivematerial may include a viscous state, wherein, for example, theconductive material includes a material in a granular solid state.Furthermore, according to one embodiment, the flexible material may beor include a first flexible material and the conductive material may beor include a second flexible material.

The preceding description only describes exemplary embodiments of theinvention. The features disclosed therein and the claims and thedrawings can, therefore, be important for the realization of theinvention in its various embodiments, both individually and in anycombination. While the foregoing is directed to embodiments of thepresent invention, other and further embodiments of this invention maybe devised without departing from the basic scope of the invention, thescope of the present invention being determined by the claims thatfollow.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of the specificembodiments discussed herein. Therefore, it is intended that thisinvention be limited only by the claims and the equivalents thereof.

1. An integrated circuit comprising: a circuit chip comprising a firstcontact field on a chip surface; an insulating layer on the chipsurface, the insulating layer comprising a flexible material; and acontact pillar being coupled to the first contact field and extendingfrom the chip surface through the insulating layer, the contact pillarcomprising a conductive material.
 2. The integrated circuit of claim 1,further comprising: a contact pad on the insulating layer, the contactpad being coupled to the contact pillar.
 3. The integrated circuit ofclaim 1, the flexible material comprising: any one of the group a groupconsisting of a photoresist material, a permanent photoresist material,a chemically amplified photo resist, a resin, an epoxy resin, epoxybis-phenol-A novolakoliomer, a sulphonium crivello salt,γ-butyro-lacton, cyclo-pentanone, polymethylmethaacrylate, TMMF, TMMR,and NANOTM SU-8, and combinations thereof.
 4. The integrated circuit ofclaim 1, the conductive material comprising: any one of the group of asolder material, tin, copper, silver, lead, bismuth, indium, a bond wirematerial, gold, and/or aluminium.
 5. The integrated circuit of claim 2,comprising: a solder ball being arranged on the contact pad.
 6. Theintegrated circuit of claim 1, comprising: a package, the package atleast in part surrounding the circuit chip and the insulating layer. 7.The integrated circuit of claim 1, comprising: a package, the package atleast in part surrounding the circuit chip, and the insulating layerbeing arranged on the chip surface and the package.
 8. The integratedcircuit of claim 1, comprising: a further contact pillar being coupledto a further contact field of the circuit chip, the further contactpillar comprising a larger cross-section than the contact pillar.
 9. Theintegrated circuit of claim 1, comprising: a group of further contactpillars being coupled to a further contact field of the circuit chip,the further contact pillars of the group being arranged surrounding thecontact pillar.
 10. The integrated circuit of claim 1, comprising: ahollow contact pillar being coupled to a further contact field of thecircuit chip, the hollow contact pillar being arranged surrounding thecontact pillar.
 11. The integrated circuit of claim 1, comprising: afurther insulating layer on the insulating layer; an intermediate signalline between the insulating layers; and a further contact pillarextending through the further insulating layer, the intermediate signalline coupling the two contact pillars.
 12. The integrated circuit ofclaim 1, comprising: the conductive material on a side face of theintegrated circuit.
 13. The integrated circuit of claim 1, comprising:the conductive material on an edge of a side face of the integratedcircuit.
 14. The integrated circuit of claim 1, comprising: a chipstack, the circuit chip being part of the chip stack.
 15. A circuitsystem comprising a circuit board comprising a contact pad on a boardsurface; and an integrated circuit being arranged on the board surface,the integrated circuit comprising a circuit chip comprising a contactfield on a chip surface; an insulating layer on the chip surface, theinsulating layer comprising a flexible material; and a contact pillarbeing coupled to the first contact field and extending from the chipsurface through the insulating layer, the contact pillar comprising aconductive material, and being coupled to the contact pad of the circuitboard.
 16. The system of claim 15, comprising: a further contact padbeing coupled to the contact pillar; and the further contact pad of theintegrated circuit being coupled the contact pad of the circuit boardusing a solder connection.
 17. The system of claim 15, comprising apackage, the package being arranged on the board surface and surroundingthe integrated circuit.
 18. The system of claim 15, the circuit systembeing any from the group consisting of a memory module, asystem-in-package, a computer mainboard, a multi chip module, or a partthereof.
 19. A method of fabricating an integrated circuit comprising acircuit chip, the circuit chip comprising a contact field on a chipsurface, the method comprising: providing an insulating layer on thechip surface, the insulating layer comprising a flexible material;providing a hole in the insulating layer in an area of the contactfield, rendering the contact field accessible; and filling the hole witha conductive material, forming a contact pillar extending through theinsulating layer.
 20. The method of claim 19, providing the insulatinglayer comprising a spin coating of the flexible material in a liquidstate and curing the liquid flexible material.
 21. The method of claim19, the insulating layer being photo-sensitive and providing the holecomprising a patterned exposure of the insulating layer and developingthe insulating layer.
 22. The method of claim 19, the filling of theholes of the insulating layer comprising: providing a first pressure inthe hole of the insulating layer; providing a bath of the conductivematerial in a liquid state to an aperture of the hole; and providing asecond pressure acting on the bath of the conductive material in aliquid state, the second pressure being greater than the first pressure.23. The method of claim 19, the method comprising providing a signalline on the surface of the insulating layer, the layer surface beingopposite to the circuit chip.
 24. The method of claim 19, the methodcomprising a providing of a contact pad on the surface of the insulatinglayer, the layer surface being opposite to the circuit chip.
 25. Themethod of claim 24, the method comprising a providing of a solder ballon the contact pad.